Industrial lift truck with clamp attachment



Jan. 18, 1955 E. L. BERTRAM 2,699,879

INDUSTRIAL LIFT TRUCK WITH CLAMP ATTACHMENT Filed.Nov. 5, 1949 5 Sheets-Sheet 1 ,Jan. 18, 1955 E. L. BERTRAM 2,699,879

INDUSTRIAL LIFT TRUCK WITH CLAMP ATTACHMENT Filed Nov. 5, 1949 5 Sheets-Sheet 2 [aw/h L Bert/am Jan. 18, 1955 E. BERTRAM 2,699,879

INDUSTRIAL LIFT TRUCK WITH CLAMP ATTACHMENT Filed Nov. 5, 1949 5 Sheets-Sheet 3 Even-for [aw/n A. Bari/am E. L. BERTRAM Jan. 18, 1955 Filed Nov. 5, 1949 INDUSTRIAL LIFT TRUCK WITH CLAMP ATTACHMENT 5 Sheets-Sheet 4 [mu/77 Bent/0m Jan. 18, 1955 E. BERTRAM 2,699,879

INDUSTRIAL. LIFT TRUCK WITH CLAMP ATTACHMENT Filed NOV. 5, 1949 5 Sheets$heet 5 flu suffer [mu/77 L. Bari/am by @M M W .flfizarnqys INDUSTRIAL LET TRUCK WITH CLAMP ATTACHMENT Edwin L. Bertram, Kenmore, N. Y., assignor to National V Gypsum Company, Bufialo, N. Y.

Application November 5, 1949, Serial No. 125,811 11 (Ilaims. (Cl. 214653) This invention relates to industrial lift trucks and particularly to a novel load-engaging, lifting and maneuvering arrangement.

in recent years electrically propelled industrial fork lift trucks have come into common use for moving'm'aterials about factories, warehouses, and the like. These fork lift trucks generally engage beneath pallets or other supports or containers for the material to be moved. In the case of the apparatus of the present invention, means are provided for engaging beneath opposed side edges of stacks of sheet material, such, for instance, as plasterboard, insulation board, plywood, sheet metal, or sheets generally. This apparatus eliminates the necessity for using skids or pallets or similar supports for the load to be transported when materials of this kind are to be moved. However, the novel lift truck arrangement of the present invention may be employed in lifting articles resting on pallets, skids or other supports Where desired.

According to the present invention the main body of the lift truck which comprises a self-contained electrically propelled automotive unit has a forwardly extending boom, which is moved over the load to be transported by generally forward movement of the lift truck proper. This boom carries beneath it at its outer end means which extend downwardly at opposite sides of the load and has portions which engage therebeneath-at opposite side edges.

The boom is pivoted to the automotive portion of the lift truck near its inner end and the depending carrier means at the outer end of the boom is pivoted to the boom, both pivots being about generally vertical axes. The apparatus is provided with power means 'forprodu'cing controlled rotation of the boom on its inner 'pivo'tal support and rotation of the suspended'work-engagingand lifting means about its pivotal connection with the outer end of the boom. The boom itself is raised and lowered at will by power means acting between the boom support and the truck proper'in much the same manner as the usual fork lift mechanism is raised and lowered in conventional lift trucks.

By reason of the present arrangement it is possible to use the lift truck to deposit loads where they could not be deposited by the use of conventional lift trucks and the apparatus further permits accurate spotting or placing of loads without relying on the degree of accuracy to which the automotive truck itself may be maneuvered. In other words, after a truck has brought a load to an approximate location,'the boom andthe loadengaging means carried thereby may both be maneuvered, with the automotive portion of the truck at rest or .in conjunction with further movement-of the truck, "to either engage or deposit a load at exactly the point desired. Further, the conjoint pivotal movements referred to above can be utilized to eifect loading and unloading operations with stacks of materials either crosswise or lengthwise. The truck proper maybe at an endof "an oblong stack of sheets or similar articles when the articles/are being picked up and may be located at the side -of rsuchista'c-le, when the load is deposited, or vice-'versa.

The advantages of maneuverability of the load-carrying portion :of the truck relative to the truckproper are of particular advantage in loading freight cars and in similar operations where the area is somewhat constricted. Lift trucks heretofore available could not be employed in many operations because of this directional limitation. Further, the maneuverability mentioned above enables the movement of a loaded .-1ift truck through passages and around cornerswhieh could :not be States Patent" 0 .ings, wherein a single 2,699,879 Patented Jan, 18,1955

negotia'ted if the load and the mobile portion cf'thetruck had fixed relative end-'to-end positions, as is generally the case. In'thecase' of the present apparatus, a corner may be turned with the load and the truck in angular relation, in much the same manner as a liighwa'y'tra'ctortrailer outfit.

The actual load+engaging elements of the apparatus Of the present invention are likewlse novel in that they provide for ready engagement beneath the side edges of a 'load even when that load lies close "to a wall or other stack of material and also permit a load to be released and deposited close to another load or wall or other 'obstru'ction and further permit the load-engaging elements to be-freely withdrawn despite such obstructions.

Various other objects and advantages attendant upon the use of the apparatus of the present invention will occur to those skilled in the art from a study of 'the 'following detailed description-and theaccompanying drawcompleteembodiment 'of the invention .is set forth by way of example. It is to be understood, however, that various mechanical modifications 'can be effected without departing from thespiritof the present invention, and that its scope is not to be consideredas limited, otherwise than as defined in the-appended claims.

In the drawings: Fig. l is-a side elevational view of one form of the apparatus of the present invention with the conventional lift truc'k-propershown fragmentarily;

Fig. '2 is a top plan view of the apparatus of -Fig.'.-1.; Fig. 3 is a fragmentary cross-sectional view on the line 3-3 of Fig. 1, buton a larger'scale;

Fig. '4 .is a fragmentary cross-sectional view on the line 4-4 of Fig. 2, likewise on an enlarged scale;

'Fig. 5 .is a fragmentary cross-sectional view "on the .line5-5-of:Fig. *1; Fig. 6 :is .a fragmentary cross-sectional view-on the line 6-16 of Fig. 5 and 'Fig. 7 is aa schematic view showing the fluid pressure connections for operating the carriage parts of the apparatusr v I Throughout the several figures "of [the drawings, like characters of reference denote like parts. :It is to be understood that the truck proper, or-what may be called the tractor portion of the apparatus, including thergreund wheels and the motive means, are all conventional and will notabe disclosed herein, excepting fragmentaril-y an'd inferentially. In Figs. 1 and 2 the numeral 10 designates the forward endof the'automotive portion of at-conventiona-l lift truck, oneof its forward wheels being indicated at 11in Fig. 1. A framework, including a pair of upright outwardly directed channels, is designated 12-- in Figs. .1 and 2, this framework being secured rigidly" to the forward ,portion of truck '10.

An. intermediate vertically sliding framework is desig nated 1-3 in .Figs. 1 and 2 and includes rollers 14'for vertical tracking engagement in the channels of'framcwork 1 2. Theintermediate framework 13 likewise is-pro v-idedwith outwardly directed channel formations, and the bracket designated generally 16 in Figs. 1 'ande2 F1188 a back wall portion 17, whose rear face carries supports :18 for rollers 19 which mount bracket 16 for free vertical movement relative to intermediate 'frameworki1'3 by tracking engagement of 'the'rollers 19in the "channels of intermediate framework 13. j

A boom designated generally 20 in Figs. 1 and Z is supported by bracket 1'6 for pivotal movement about a generally vertical axis. Reference will now be had particularly to Figs. 3 and 4, which illustrates in detailathis pivotal connection. Bracket 16 includes upper and lower horizontal plate portions 22 and 23, which project .forwardly from rear wall 17 and screw means 25 comprises avertically.adjustablesupport for an upper tapered roller bearing .26, while similar screw means 27 provide a-vertically adjustable support for a lower tapered roller bearingw28.

.A vertical sleeve 30 engages about the roller bearings 26 and 28 at its upper and lower ends, and at its lower end i-scsfixed 'to za generally horizontal plate element 31 by meanssof screws or otherwise. Plate element 31' rests concentric with a vertical pivot axis for upon an annular thrust roller bearing 32 which in turn is supported by lower plate portion 23 of bracket 16.

e main framework for boom comprisees a U- shaped channel element 33 whose opposite legs extend rearwardly and are fixed to the upper opposite side edges of plate element 31 as at 35 and 36 in Figs. 3 and 4. The arcuate forward intermediate portion of U-shaped channel member 33 is designated 38 in Fig. l and is generally a carrier unit which is designated generally 40 in Figs. 1 and2, the carrierunit being suspended beneath the arcuate portion 38 of channel element 33.

This pivotal connection is illustrated in detail in Fig. 5

'and Will now be described generally. Upper and lower plateelements 41 and 42 are fixed to the upper and lower surfaces of the portion 38 of channel element 33. A mounting sleeve for carriage 40 is designated 44 and has an intermediate annular flange 45 which rests upon an axial thrust roller bearing 46, which in turn rests upon and is supported by lower plate 42 of the outer end of boom 20.

A main central mounting plate for carriage 40 is designated 48 and includes a hub portion 49 which is keyed to sleeve 44 asat 50 and is held thereon by nut means 53 which engage the threaded lower end of sleeve 44. The weight of carriage 40 and the loads carried thereby normally maintain sleeve 44 in proper axial position with its flange 45 resting upon thrust bearing 46.

The carrier mounting plate 48. which is thus fixed to sleeve 44 for pivotal movement therewith, is of sutficient extent fore and aft of the ma hine to overlie a pair of transverse angle irons 55 and 56 as shown in Figs. 1 and 2 and is of sufficient extent laterally to underlie a pair of longitudinally extending channel members 57 and 58. The transverse angle irons 55 and 56 and the lon itudinal channel members 57 and 58 are all securely welded to mounting plate 48 and a second pair of outer longitudinal channel members 60 and 61 are welded to the outer ends of angle irons 55 and 56, vertical spacing plates 62 being interposed between channel members 60 and 61 and the upper surfaces of angle irons 55 and 56 to position channel members 60 and 61 at the same elevation as channel members 57 and 58. as shown in Figs. 5 and 6.

At their front ends the channel members 57, 58, 60, and 61 su ort a pair of spaced transverse facing channel elements 65 and 66, the latter being positioned with their upper surfaces against the under surfaces of channel members 57. 58, 60, and 61 and being welded to those channel members.

At their rear ends channel members 57, 58. 60. and 61 similarly support a pair of facing channel elements 68 and 69. The channel elements 65. 66. 68, and 69 provide trackways whose ends are closed by plates which are fixed to the outer surfaces of outer channel members 60 and 61, the pla es being designated 70, 71, 72, and 73, respectivelv, in Figs. 1 and 2.

'The portion of the structure which has iust been described comprises an integral rigid carrier framework. all of the structural arts of the carrier thus far described being fixed securely to sleeve 44 to pivot therewith about its vertical axis. Reference will now be had to portions of the carrier structure which move inwardly and outwardlv selectively relative to the fixed carrier structure, and which have other elements pivotally movable to engage and disengage beneath loads to be transported.

Referring particularly to Figs. 5 and 6, the movable carriage element which appe rs at the lower left-hand part of the carrier in Fig. 2 is illustrated. there being four such carriages. one at each corner of the framework of carrier 40. This carriage is designated generally 78 and comprises a pair of side walls 88 and 81 and an outer end wall 82. A air of bearings 83 and 84 are fixed between walls and 81 in any desired manner, see Fig. 2, and shafts 85 and 86 bearing therein, res ectively, are provided with pairs of rollers 87 and 88 at their opposite ends, which rollers ride in the pair of facing channels 68 and 69.

Side walls 80 and 81 have portions which depend below channels 68 and 69 and have secured against their outer surfaces a pair of channels 90 and 91 which give pivotal support to the inner end of a hydraulic cylinder 95 as at 96. The function of hydraulic cylinder 95 will presently be described.

A pair of depending angle irons 98 and 99 have the upper portions of one edge of their flanges removed whereby the remaining flange of each channel may be fixed against the inner depending portion of each wall 80 and 81, as at 100 and 101 in Fig. 6. Angle irons 98 and 99 extend rigidly downwardly from the walls 80 and 81 of the carriage being described and, referring to Fig. 5, give pivotal support to a lever 183 as at 104. Lever 103 lies between angle irons 98 and 99, and its upper and igWfili projecting portions are bifurcated as shown in The upper portion of lever 104 pivotally engages a piston rod 106, which extends from the piston (not shown) of hydraulic cylinder 95. The carriage element which appears at the lower right-hand corner of Fig. 2 is identical with that just described, and in Figs. 1 and 2 is designated generally 108. The lower bifurcations of lever 103 of carriage 78 and the bifurcations of the corresponding lever 103 of carriage 108 are secured to the outer and lower walls of an L-shaped longitudinal lever 110 as best shown in Figs. 1 and 5.

It will be clear from the foregoing that inward movement of the pistons of hydraulic cylinders 95 of the carriage portions 78 and 108 will swing the L-shaped element 110 from the full-line position of Fig. 5, where it engages beneath a load or stack designated A, to the dot-anddash line position of Fig. 5, where it is clear of the bottom of the stack and may be withdrawn either vertically or horizontally in a direction perpendicular to the sheet in Fi 5.

Referring again particularly to carriage '78, as illustrated in Figs. 2 and 5, a hydraulic cylinder has its inner end fixed in any desired manner as to a cross bar 116, which is secured over channels 68 and 69. Hydraulic cylinder 115 has a piston, not shown, and a piston rod 117 projects outwardly therefrom and is fixed at its outer end to the inner bearing 83 of carriage 78. The corresponding carriage 188 at the lower righthand corner of Fig. 2 is similarly provided with a hydraulic cylinder 115 and simultaneous movement of both piston rods 117 either inwardly or outwardly moves the two carriage units 78 and 108 at one side of the carriage to move L-shaped element 110 and its supporting structure bodily inwardly and outwardly.

Referring to Fig. 2, the opposite side of the carrier is provided with carriage units which are designated generally 120 and 121, which are identical with the carriages 78 and 108 to which reference has previously been made. Referring to Fig. 7, the four hydraulic cylinders 95 are indicated schematically and operate in unison to swing L-shaped element 110 and a corresponding L-shaped element at the opposite side of the carrier outwardly and inwardly by pivotal movement of the several bifurcated levers 103 of the four carriage units.

The four hydraulic cylinders 115 illustrated in Fig. 7 operate in unison to move the four carriage units 78, 108, 120, and 121 simultaneously inwardly and outwardly by rolling movement of wheels 87 and 88 in channels 65, 66, 68, and 69.

In Fig. 7 the numeral 125 designates an electrical motor which may be mounted in any convenient position on the truck proper and is connected directly to a pump 126 which has an outlet pressure conduit 127 leading to a pair of conventional four-way valves 128 and 129. These four-way valves are well-known and widely used in the mechanical arts generally and need not be illustrated in detail. Suflice it to say that they are normally neutral and operable selectively to either of two positions where they connect one or the other end of each hydraulic cylinder to operating pressure from conduit 127, the opposite end of the cylinder being automatically then connected to discharge.

Externally, each of the four-way valves 128 and 129 have a hydraulic pressure connection 127 and a common drain connection 131 which leads back to a reservoir 132 which, in turn. connects with the intake side of pump 126 as at 133. A third conduit leading from four-way valve 128 is designated 135 and branches out to lead to the outer end of each hydraulic cylinder 95. A fourth conduit leading from four-way valve 128 is designated 136 and leads to a junction box 137, where it connects freely with four branch passages 138, each leading to the inner end of one of the hydraulic cylinders 95.

The four-way valve 129 similarly has conduits 140 and 141 which lead, respectively, to the outer and inner ends of the four hydraulic cylinders 115. Valves 128 and 129.,may be solenoid-operated. by remotepush button means i'n'conventional manner. in Fig. la control panel 145 is shown mounted upon. framework 12.- so as to be conveniently accessiole to a lift truck operator.

in. Fig. 1 a controlbutton 146 may be'depressed to electromagnetically move the control means in fourway valve. 128 from neutral position, where all passages leading therefrom are blocked, to a position. where pressure conduit 121 connects freely with conduit 135 and conduit 136 is connected freely with drain conduit 131. This causes the pistons of hydraulic cylinder 95 tomove inwardly as long as the operator keeps button 146 depressed and moves L-shaped member and the corresponding opposite L-shaped member to the loadreleasmg position. shown in dot-and-dash lines at the bottom of Fig. 5.

Depression of a second control button 147 on panel 145 reverses the. connections in the four-way valve so that conduits 136 and 138 are pressure-connected, and conduit 135 connects with the drain. This operation moves the L-shaped members to their load-engaging position as illustrated in full lines at the bottom of Fig. 5.

Four-way valve 129, which is also normally neutral, is controlled by a pair ofpush buttons 150 and 151 which selectively condition four-way valve 129 to. connect eitherthe inner or the outer ends of'cylinders 115 with the. pressure line 127, the opposite ends of the cylinders being simultaneously connected to drain 131 through the four-way valve.

The U-shaped channel element 33 which makes up the principal part of boom is reinforced by means of 'a' pair of structural bars 155 and 156, see Figs. 1 and, 2, the bars extending divergently from the upper portion of bracket 16 to the upper inner end of plate 41. An inverted channel member 158 extends. outwardly in a generally horizontal direction from bracket 16 and is supported at its outer ends by a pair of supports 160 which extend downwardly divergently therefrom to engagement with the opposite sides of U-shaped channel element 33. Channel member 20 serves as a housing for the hydraulic conduits leading from bracket 16, those conduits beingdesignated collectively 161 in Fig. 1 and" extending downwardly through hollow, sleeve 44 which forms the pivot axis of carrier 40 for pivotal movement about the outer portion of boom 20.

Reference will now be had to the means for slewing boom 20 angularly about, the axis of sleeve 30, and in this connection reference is bad particularly to Figs. 3 and 4. A gearsector165iisfixed. to the upper portion of..sleeve 30, and meshes with a pinion 166,. which is fixed to the output shaftof a conventional speed-reducing gear unit 167; the latter in turn being connected to; the output shaft of a reversible electric driving motor 168. Controlbuttons 170 and 1'71 on panel 145, Fig. l, arev manuallyoperable to energize motor 168for rotation in: opposite directions to selectively swing, or slew boom 35 ina horizontal direction about pivot sleeve 30.

The entire carrier unit 40-is rotatable about the vertical, axis of sleeve44,-Fig. 5, and the manner in which such rotation is selectively effected appears best in Figs. 2, 3;, and 5. A'sprocket 175 is fixed to the supporting: flange 45- of rotatable sleeve 44 and is adapted to be connected by means of a chain 176 with a smaller sprocket 177 to be driven thereby. Referring to Fig. 3, an electric drivingmotor 180 is mounted in bracket 16 ;and has connected therewith a conventional speedrerlucing gear unit 181-, the sprocket 177 being secured to; the outputshaft of-thelatter; Here again, control buttons 1'84and185-on thecontrol panel 145 selectively energize motor 180 which is of the reversible type so that carrier 40 may be rotated angularly in either direction, as, for instance, to the dot-and-dash line position illustrated in Fig. 2.

What is claimed is:

1. In a lift truck, a power operated tractor unit, a support mounted at the front of said tractor unit and power means for raising and lowering said support bodily in a vertical direction relative to the tractor unit, a boom extending horizontally forwardly from said support and pivoted thereto for swinging movement about a generally vertical axis, load engaging means comprising a pair of spaced side frame elements including means at their lower portions for engagement beneath opposite side edges of a load, and pivot means suspending said load engaging means from the outer portion of said boom for ,rotative movement generallyabout the vertical axis .of said load engaging means, power means operative to. swing. saidboorn. on its pivotal connection with said support, and power means operative to rotate said load engaging and carrying means relative to the outer portion of said boom, and remote control meanson said tractor unit operableselectively to. control both of said power means.

2, In a lift truck,a power operated tractor unit, a boom extending horizontally forwardly from said tractor unit and pivoted theretofor swinging movement about a gen: erally vertical axis, power means for raising andlowering said boom bodilyvertically relative to the tractor unit, load engaging means comprising a pair of spaced side frame elements including means at their lower portions for engagement beneath opposite side edges. of a load, andpivot means suspending said load engaging means from the outer portion of said boom for rotative movement generally about the vertical axis of said load engaging means, power means operative tosw-ing said boomon its pivotal connection withsaid support, and power means operative to rotatesaid load engagingmeans relative to the outer portion of saidboom, and remote control'means on said tractor unitoperable selectively to control both of said power means.

3. In a lift truck, a power operated tractor unit, a boom extending horizontally forwardly from said tractor unit: and pivoted theretofor swinging movement about a generally vertical. axis, power means for raisingand lowering saidboom bodily vertically relative to the tractor unit, load v engaging means comprising a. pair of. spaced side frameelements including means at their lower portions for engagementbeneath opposite side edges of a load, said load engaging means being pivotally supported by the outer portion of said boomforrotative movement generally about the vertical axis of said load engaging means power means operativeto swing said boom on 'its pivotal. connectionv with. said support, and power means operative to rotate said load engaging means relative to the outer portion of said boom, and remote control means on said tractor unit operable selectively to control'both of said power means.

4. In: a lift truck, a poweroperated tractor unit, a boom extending, horizontally forwardly from said tractor. tmit and having a portion thereof movable laterally relative thereto, power means for raising and. lowering said boom bodily-vertically relative to the tractor unit, load.

engaging means comprising a pair of spacedside frame elements including means at their lower portions for engagement beneath. oppositesideedges of a load, said load engaging means being pivotally supported by the outer portion of said boom for rotative movementgem erally about the vertical axis of said load engaging means, power means operative to move said. boom laterally, and power means operative to rotate said load engaging means relative to the outer portion of said boom, and remotecontrol means. on said tractor unit operable selectively to control both-of said power means.

5. In a lift truck, a power operated tractor unit, a support mounted at. the front of said tractor unit and power means for raising and lowering said support relative-to the tractor unit, a boom extending forwardly from said support and pivoted thereto for swinging movement about a generally vertical axis, load engaging and carrying means comprising a pair of spaced side frame elements including means at their lower portionsfor engagement beneath opposite side edges. of a load, and pivot means suspending-said load-engaging and carrying'means from the outer portion of said boom for rotative movement about a generally vertical axis, power means operative to swing said boom on its pivotal connection with said support, and power means operative to rotate said load engaging and carrying means relative to the outer portion of said boom, and remote control means on said tractor unit operable selectively to control both of said power means, and power means for moving said side frame elements toward and away from each other.

6. In a lift truck, a power operated tractor unit, a support mounted at the front of said tractor unit and power means for raising and lowering said support relative to the tractor unit, a boom extending forwardly from said support and pivoted thereto for swinging movement about a generally vertical axis, load engaging and carrying means comprising a pair of spaced side frame elements including means at their lower portions for engagement beneath opposite side edges of a load, and pivot means suspending said load engaging and carrying means from the outer portion of said boom for rotative movement about a generally vertical axis, power means operative to swing said boom on its pivotal connection with said support, and power means operative to rotate said load engaging and carrying means relative to the outer portion of said boom, and remote control means on said tractor unit operable selectively to control both of said power means, and remote control means for moving the means at the lower portions of said side frame elements toward and away from each other to engage beneath or move out of engagement with a load.

7. In a lift truck, a power operated tractor unit, a support mounted at the front of said tractor unit and power means for raising and lowering said support rela' tive to the tractor unit, a boom extending forwardly from said support and pivoted thereto for swinging movement about a generally vertical axis, load engaging and carrying means comprising a pair of spaced side frame elements including means at their lower portions for engagement beneath opposite side edges of a load, and pivot means suspending said load engaging and carrying means from the outer portion of said boom for rotative movement about a generally vertical axis, power means operative to swing said boom on its pivotal connection with said support, and power means operative to rotate said load engaging and carrying means relative to the outer portion of said boom, and remote control means on said tractor unit operable selectively to control both of said power means, power means for moving said side frame elements toward and away from each other, and remote control means for moving the means at the lower portions of said side frame elements toward and away from each other to engage beneath or move out of engagement with a load.

8. In a lift truck, a power operated tractor unit, a boom extending forwardly from said tractor unit and having a portion thereof movable laterally relative thereto, power means for raising and lowering said boom relative to the tractor unit, load engaging means comprising a pair of spaced side frame elements including means at their lower portions for engagement beneath opposite side edges of a load, said load engaging means being pivotally supported by the outer portion of said boom for rotative movement generally about the vertical axis of said load engaging means, power means operative to move said boom laterally, and power means operative to rotate said load engaging means relative to the outer portion of said boom, remote control means on said tractor unit operable selectively to control both of said power means, and power means for moving said side frame elements toward and away from each other.

9. In a lift truck, a power operated tractor unit, a boom extending forwardly from said tractor unit and having a portion thereof movable laterally relative thereto, power means for raising and lowering said boom relative to the tractor unit, load engaging and carrying means comprising a pair of spaced side frame elements including means at their lower portions for engagement beneath opposite side edges of a load, said load engaging and carrying means being pivotally supported by the outer portion of said boom for rotative movement about a generally vertical axis, power means operative to move said boom laterally, said power means operative to rotate said load engaging and carrying means relative to the outer portion of said boom, remote control means on said tractor unit operable selectively to control both of said power means, and remote control means for moving the means at the lower portions of said side frame elements toward and away from each other to engage beneath or move out of engagement with a load.

10. In a lift truck, a power operated tractor unit, a boom extending forwardly from said tractor unit and having a portion thereof movable laterally relative thereto, power means for raising and lowering said boom relative to the tractor unit, load engaging and carrying means comprising a pair of spaced side frame elements including means at their lower portions for engagement beneath opposite side edges of a load, said load engaging and carrying means being pivotally supported by the outer portion of said boom for rotative movement about a generally vertical axis, power means operative to move said boom laterally, and power means operative to rotate said load engaging and carrying means relative to the outer portion of said boom, remote control means on said tractor unit operable selectively to control both of said power means, power means for moving said side frame elements toward and away from each other, and remote control means for moving the means at the lower portions of said side frame elements toward and away from each otherdto engage beneath or move out of engagement with a oa 11. In a lift truck, a power operated tractor unit, a boom extending forwardly from said tractor unit and pivoted thereto for swinging movement about a generally vertical axis, power means for raising and lowering said boom relative to the tractor unit, load engaging and carrying means comprising a pair of spaced side frame elements including means at their lower portions for engagement beneath opposite side edges of a load, and pivot means suspending said load engaging and carrying means from the outer portion of said boom for rotative movement about a generally vertical axis, power means operative to swing said boom on its pivotal connection with said support, and power means operative to rotate said load engaging and carrying means relative to the outer portion of said boom, remote control means on said tractor unit operable selectively to control both of said power means, and remote control means for moving the means at the lower portions of said side frame elements toward and away from each other to engage beneath or move out of engagement with a load.

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Mullgardt Dec. 9, 1952 

